In the field of electrophotography development powders are used to develop an electrostatic image on a photoconductive surface. There are generally two types of dry development powder, single component and dual component. The dual component development comprises carrier particles such as iron filings or glass beads and toner particles which are attracted by electrostatic charge to the carrier particles. Because the carrier particles are of a large size and the toner particle attracted thereto are of a relatively small size, large quantities of dual component development powder may be stored in a dispensing unit without concern of the compression effect, i.e. the development powder at the bottom of the dispenser being crushed due to the pressure created by the large volume. This is not true in the use of a single component development powder or toner particles that are stored for replenishment purposes. A single component development powder is generally made of a homogeneous toner particle containing a magnetic substance such as magnetite. With regard to a dual component development powder, theoretically only the toner portion is consumed during development and this toner must be replenished. When a large quantity of single component development powder or toner material is stored, a "pressure head" is developed at the bottom of the storage hopper. Single component development powder and toner particles inherently lack compression strength so that storing a large amount of such materials in a dispensing unit is difficult due to the compression effect, and in many cases, these materials are designed, chemically, to permit pressure fixing and thus form agglomerates more readily. Additionally, the action of the fluctuating magnetic field used to transport the material to the development zone can act to detrimentally compact the toner in certain regions of the development sump. Thus, obviously, it would be desirable to be able to store large quantities of single component development powder or toner particles without having to be concerned about the particles being crushed due to the compression effect.